Sarumen - Alaria esculenta

Scientific classification

Domain:          Eukaryota

(unranked):     SAR

Superphylum: Heterokonta

Class:   Phaeophyceae

Order: Laminariales

Family:            Alariaceae

Genus: Alaria

Species:           A. esculenta

Binomial name           Alaria esculenta

(Linnaeus) Greville

Alaria esculenta is an edible seaweed, also known as dabberlocks or badderlocks, or winged kelp. It is a traditional food along the coasts of the far north Atlantic Ocean.

It may be eaten fresh or cooked in Greenland, Iceland, Scotland and Ireland. It is the only one of twelve species of Alaria to occur in both Ireland and in the Great Britain.

Grows to a maximum length of 2 m. The whole frond is brown and consists of a distinct midrib with wavy membranous lamina up to 7 cm wide on either side.

The frond is unbranched and tapers towards the end. The base has a short stipe arising from a rhizoidal holdfast. The stipe may bear several sporophylls which are club-shaped and up to 20 cm long and 5 cm broad which bear the spores.

It grows from a short cylindrical stipe attached to the rocks by a holdfast of branching root-like rhizoids and grows to about 20 cm long.

The stipe is continued into the frond forming a long conspicuous midrib, all other large and unbranched brown algae to be found in the British Isles are without a mid-rib. The lamina is thin, membranous with a wavy margin.

Alaria esculenta is well known in Ireland, where it is known as Láir or Láracha, and in the British Isles save the south and east of England. It is perennial.

It is a common large algae on shores where there is severe wave exposure attached to rocks just below low-watermark in the "Laminaria belt", and is common on rocky shores in exposed places.

It has a fairly high intrinsic growth rate compared to other algae, 5.5% per day and a carrying capacity of about 2 kg wet weight per square meter. It may reach lengths of about 2.5 m. It overlaps to a small degree (+) in distribution with Fucus serratus and somewhat more with Laminaria digitata.

It has low and high light limitation values of about 5 and 70 W per square meter respectively. Its distribution is also limited by salinity, wave exposure, temperature, desiccation and general stress. These, and other attributes of the algae are summarized in Lewis (1964) and Seip 1980.

Leaf-like sporophylls develop from the stipe and produce zoospores.

Esculenta may produce phlorotannins and oxidized lipids as protective functions against high photosynthetically active and UV radiations.

Alaria is a genus of brown alga (Phaeophyceae) comprising approximately 17 species. Members of the genus are dried and eaten as a food in Western Europe, China, Korea, Japan (called sarumen), and South America.

Distribution of the genus is a marker for climate change, as it relates to oceanic temperatures.

The most common species, Alaria esculenta is a large brown seaweed common on the shores of the British Isles. It has been studied for its potential for aquaculture.

Alaria is a genus of highly variable brown algae, and a member of the order Laminariales, more commonly known as kelp. It has mature sporophytes as small as 15 centimetres (5.9 in) and as large at 15 metres (49 ft) in length.

All species’ sporophytes consist of a ramified holdfast, an unbranched cylindrical stipe, and a blade with a percurrent, cartilaginous midrib, Alaria is frequently found with lacerations running from the margin to the midrib caused by the ravages of the sea.

Alaria the second largest genus of Laminariales, with about 17 currently recognized species. However, due to its highly plastic morphology, the kelp has over 100 specific and subspecific names, which have arisen since it was first described in 1830.

Alaria is most commonly found in far northern waters of the Pacific and Atlantic oceans, with the greatest variety of species concentrated in the north Pacific.

More specifically, it has been found on the coasts of England, Ireland, Scotland, Iceland, Greenland, Denmark, Norway, Japan, China, Korea, Canada, and the United States.

Alaria is typically found in the sublittoral zones, at a depth of 3–10 metres (10–33 ft). An important factor in Alaria’s distribution is temperature; it is limited by sea temperature of 16°C. and greater.

Presumably due to this factor, and rising sea temperatures, the genus has largely disappeared from the English Channel within the past 100 years.

Recent research conducted on Alaria esculenta in the Arctic showed pronounced temperature effects on the photosynthesis and germination of the algae.

In Ireland, Scotland, Greenland, Iceland, Denmark, and the Faroe Islands, the midrib is removed, and the blade and sometimes the leaflets are eaten, although it is not commercially available.

It is more commonly eaten in the Far East (China, Japan, and Korea), where seaweed consumption is much more popular than in the West. Seaweeds are considered to be highly nutritious, because typically they are low in fat, and have vitamins and minerals in amounts comparable or superior to terrestrial vegetables. Alaria esculenta, in particular, is an excellent source of protein and iodine.

As with all kelps, Alaria demonstrate a heteromorphic, sporic life history, with a macroscopic, dominant sporophyte, and a microscopic gametophyte.

Unique to the genus Alaria is that the sori of the unilocular sporangia are restricted to certain blades, the sporophylls. The sporophylls are formed as lateral blades from the stipe.

Most species are perennial; after reproduction, the blade sloughs off, leaving the stipe and meristem. The persisting meristem produces a new blade at the beginning of the next growing season.

The species currently recognised are:

A. angusta

A. crassifolia, sarumen, ezo-wakame

A. crispa

A. dolichorhachis

A. elliptica

A. esculenta

A. fragilis

A. grandifolia

A. marginata

A. oblonga

A. paradisea

A. praelonga

A. pylaiei